1. Field of the Invention
The present invention relates generally to data collection and transmission, and more particularly to collecting data from an array of sensors aboard an unmanned vehicle, digitizing the data for transmission over a local area network and displaying the data at a site remote from the vehicle.
2. Description of the Prior Art
There are many well known applications wherein analog data is collected from sensors, converted to digital signals, stored in a memory and then displayed. For example, U.S. Pat. No. 4,104,609 to Minegishi et al. recites a fish-finder which emits ultrasonic pulses into the water, receives the reflected waves, converts the reflected waves into digital signals, writes the digital signals into a main memory and reads out the digital signals for display on a color display. U.S. Pat. No. 5,047,990 to Gafos et al. recites an acoustic data acquisition system for shipboard use that allows for underwater acoustic data measurements at preselected submerged marine structural coordinates using a tethered, remotely operated vehicle (ROV). A fiber optic link is provided in the tether for conducting data signals from an acoustical transducer array located on the ROV to the mother ship. In order to display the sensor data, such systems as the Minegishi et al. fish-finder and the Gafos et al. system utilize memory buffering/reading schemes for transferring the data to a main memory prior to display. Such schemes are also known in the art. U.S. Pat. No. 5,099,458 to Takaki discloses a system in which sensor data is written into the transmission side of a memory. The data is then read out at constant periods using read and write address counters to point to, read, or write address positions in memory. Similarly, U.S. Pat. No. 5,128,931 to Yamanaka et al. recites a data exchange apparatus having common buffer memories for temporarily storing input data, a vacant buffer selector, i.e., pointer, for selecting a vacant buffer and memory locations to store the buffer identification numbers. The buffer memories operate independently to allow reading and writing to be carried out independently.
In certain applications, it is necessary for an unmanned vehicle to act independently, i.e. untethered, and at a considerable distance from the main, or mother ship. Unlike the Minegishi et al. fish-finder and the Gafos et al. system, the data acquisition system for such applications must be capable of processing and storing the sensor data aboard the unmanned vehicle for later transfer to the mother ship for display. Additionally, it may be necessary to provide real-time data for display in order to monitor the performance of the unmanned vehicle. None of the prior art data collection systems or data storage and retrieval methods can provide for both of these possibilities.